The present invention generally relates to a valve, and in particular to a valve of a type having a housing formed with a valve seat and having an inlet port and an outlet port, and a shut-off member positioned in a passageway between the inlet port and outlet port and so adjustable as to enable a separation of the inlet port and the outlet port from one another when resting on the valve seat.
A valve of this type is known e.g. from German Pat. No. 36 09 772 and in particular describes a valve seat which exhibits a seat surface which is so configured that the intersection of all tangents drawn on the seat surface form an imaginary cone, with the valve seat forming a slanted cut through this cone. Basically, the flow efficiency of such valves depends on the opening angle which influences the surface lines and thus the flow cross section which should be selected as large as possible in order to enable a substantially unhindered fluid passage. On the other hand, the dimensions of such valves, especially with regard to their structural length are standardized so that conventional seat surfaces cannot be configured for an optimum flow throughput. For example, a large opening cross section shaped to enhance flow dynamics cannot be realized because the standardized outer structural dimensions limit the opening angle of the cone.
Determination of the flow efficiency is dependent besides on the flow velocity and rate of flow for pure liquids also on the same parameters for solids-laden liquids. Practice has shown that in this case the application of conventional valves is problematic heretofore.